Myasthenia gravis

Myasthenia gravis is a chronic, often remitting neuromuscular disease, the main manifestation of which is the pathological fatigue of the striated muscles.

The etiology is unknown.

Pathogenesis is due to the blocking of conductivity at the level of the myoneural synapse. Apparently the complicity of autoimmune mechanisms. An important role belongs to the pathology of the thymus gland. Women are more often sick. The onset of the disease is possible at any age, but usually it is observed in youth.

Symptoms, course. The first signs - oculomotor disorders (ptosis, external ophthalmoplegia, doubling), which later join the paresis of bulbar muscles and skeletal muscles. The severity of paresis often increases by evening. Pathological fatigue of the muscles is easily detected with repeated movements (account aloud, squeezing and unclenching the brush). In this case, the pareses are aggravated or appear in intact muscle groups. Atrophy, reflex reflexes and sensitivity are not present. For a long time, weakness can be observed in a limited group of muscles, but over time the process is usually generalized. Often, under the influence of unfavorable external factors, or spontaneously there is a weakness in the respiratory muscles, sometimes with a violation of swallowing. These vital disorders are referred to as the myasthenic crisis. Electromyography reveals a characteristic myasthenic reaction. Ballistic myasthenia is contraindicated in the appointment of streptomycin, kanamycin, tetracycline, novocainamide, aminazine, diphenin, anaprilin, quinidine.

Diagnostic difficulties are not uncommon, especially in the initial stage of the disease, when the peripheral or central nervous system is suspected of hysteria. A decisive role in the differential diagnosis has a positive proserin test: intravenous injection of 1.5-2 ml of 0.05% prozerin in patients with myasthenia leads to a temporary but significant decrease in the degree of paresis.

Treatment. The systematic reception of individually selected doses of anticholinesterase drugs (proserine, kalimine). An overdose of these drugs can lead to the development of a cholinergic crisis, which in many ways resembles a myasthenic crisis. Glucocorticoids and less often other immunosuppressors (azathioprine); Plasmapheresis. Often there is a need for thymectomy or irradiation of the thymus gland. Especially energetic and persistent actions require a myasthenic crisis; And often it is necessary to transfer patients to the hardware breathing.

Forecast. 15-20% of patients die from respiratory failure or from intercurrent infections.